Expose TypeChecker.getMergedSymbol to public (#56192) (#56193)

Author: timocov

src/compiler/types.ts

@@ -5043,7 +5043,7 @@ export interface TypeChecker {
     isUndefinedSymbol(symbol: Symbol): boolean;
     isArgumentsSymbol(symbol: Symbol): boolean;
     isUnknownSymbol(symbol: Symbol): boolean;
-    /** @internal */ getMergedSymbol(symbol: Symbol): Symbol;
+    getMergedSymbol(symbol: Symbol): Symbol;
 
     getConstantValue(node: EnumMember | PropertyAccessExpression | ElementAccessExpression): string | number | undefined;
     isValidPropertyAccess(node: PropertyAccessExpression | QualifiedName | ImportTypeNode, propertyName: string): boolean;

tests/baselines/reference/api/typescript.d.ts

@@ -6778,6 +6778,7 @@ declare namespace ts {
         isUndefinedSymbol(symbol: Symbol): boolean;
         isArgumentsSymbol(symbol: Symbol): boolean;
         isUnknownSymbol(symbol: Symbol): boolean;
+        getMergedSymbol(symbol: Symbol): Symbol;
         getConstantValue(node: EnumMember | PropertyAccessExpression | ElementAccessExpression): string | number | undefined;
         isValidPropertyAccess(node: PropertyAccessExpression | QualifiedName | ImportTypeNode, propertyName: string): boolean;
         /** Follow all aliases to get the original symbol. */